Rafael Nadal has curtailed his 2021 ATP Tour season due to a long-term foot injury but insists he is working towards a return.
Nadal, 35, has played only twice since losing the French Open semi-final to Novak Djokovic in May.
The Spaniard skipped Wimbledon and the Tokyo Olympics and had withdrawn from this week's Western and Southern Open before the US Open.
Nadal will not now compete in the final major of the season either, while great rival Roger Federer is also out for an extended period.
It clears a path for Novak Djokovic – the third man tied on 20 grand slam titles – to win a record-breaking 21st championship at Flushing Meadows while completing a remarkable calendar Grand Slam.
Djokovic could yet have competition again in the years to come, though, as Nadal is not yet calling time on a glittering career.
In making his latest announcement on social media on Friday, Nadal revealed he has been dealing with his injury since 2005 but has not let it halt him yet.
"Hello everyone," he wrote on his Twitter page. "I wanted to inform you that unfortunately I have to end the 2021 season.
"Honestly, I've been suffering a lot more than I should with my foot for a year and I need to take some time.
"After having discussed it with the team and family, this decision has been made and I think it is the way forward to try to recover and recover well.
"It's a year that I've missed things that matter a lot to me, like Wimbledon, like the Olympics, how the US Open is going to be now, like many other events that are also important to me.
"And in view of the fact that during this last year I have not had the ability to train and prepare and compete in the way that I really like to do it, in the end, I come to the conclusion that what I need is time to recover, change a series of things, try to understand what has been the evolution of my foot in recent times.
"It is not a new injury, it is an injury that I have had since 2005 and it has not prevented me from developing my sports career during all these years.
"If it is true that I have had a season where things are not going as they should, as we would all like, it is time to make decisions, seek a slightly different type of treatment to find a solution to this problem or at least improve it in order to continue to have options for the next few years.
"I have the maximum enthusiasm and predisposition to do whatever it takes to recover the best possible form to keep competing for the things that really motivate me and the things that I've done all these years.
"I am convinced that with the recovery of the foot, and obviously a very important daily effort, this can be achieved. I will work as hard as I can to make it happen.
"Thank you in advance for all the support, understanding and all your expressions of affection that are very important and more in difficult times like these.
"I promise you what I am going to do is work hard to try to continue enjoying this sport for a while longer. A big hug to all."